Very hungry caterpillars

Madonna Lily
Bud and flowers (some moth-eaten) of a Madonna Lily

We have quite a few pots of Madonna Lilies (aka Peace Lilies, Spathiphyllum spp.) around the house; they do well until they are eaten, which happens with some regularity. Looking down into a pot yesterday, I saw a couple of the usual suspects lying on the dirt as though they were sleeping off their gluttony.

Continue reading “Very hungry caterpillars”

The very hungry caterpillar

black caterpillar
Caterpillar of Impatiens Hawk Moth on a well-eaten twig of Pentas. Its head is at the right.

Hawk Moths (Sphingidae) are a family of large, heavy-bodied moths whose caterpillars are similarly large and heavy-bodied, and they get that way by eating voraciously.

The Australian Museum says:

The caterpillar of the Impatiens Hawk Moth, Theretra oldenlandiae, is a common visitor to suburban Sydney gardens. It is most frequently found on Balsams, Impatiens balsamina, I. oliveri and I. wallerana, often eating all the leaves. Some other larval food plants include:

  • Arum Lily – Zantedeschia aethiopica
  • Fuchsia (any of the garden varieties)
  • Grape – Vitis vinifera

The caterpillars are black with yellow spots and strips, and have a thin spine at the end of the abdomen that has a white tip. Mature larvae can reach a length of 7 cm. The larvae pupate in a loosely woven cocoon, which they construct within leaf litter.

… Although they may eat your plants as caterpillars, hawk moths are not considered pests. The adults have an important role as pollinators of many plant species and are the most significant pollinator of papaya (pawpaw) crops.

Hawk moth caterpillars regularly attack just two species of plants in our garden, the Pentas and Madonna Lily, and one or two caterpillars can, and do, strip a plant in a matter of days. The one in my photo was evicted from a white-flowering pentas to give it (the plant!) a chance of survival.

The same site notes that Australia has 65 species of hawk moth (all the adults are shown here, with links to the caterpillars) of the 850 known worldwide. I’m not sure how many of them we have around Townsville but I have photographed adults of seven species and caterpillars of about six in my garden. (Caterpillars are hard to be sure about because each species can have two or three colour forms.)

I only have caterpillar-adult pairs of four species, however, so we have at least eight species altogether: Convolvulus Hawk Moth, Agrius convolvuliEupanacra splendens; Grapevine Hawk Moth, Hyppotion celerioHippotion rosettaDaphnis protrudens; White-brow Hawk Moth, Gnathothlibus erotus; Impatiens Hawk Moth, Theretra oldenlandiae; and Macroglossum micacea. Note that most of them don’t even have ‘common’ (i.e. English-language) names but have to get by, somehow, with Latin. I don’t think it bothers them.

Ulysses Swallowtail butterfly

Ulysses Swallowtail hovering to feed on Pentas
Ulysses Swallowtail hovering to feed on Pentas

Cairns Birdwing butterflies are, to be sure, impressively large and colourful but they still don’t deserve quite as much of the limelight as they have been getting here lately. The Ulysses (Papilio ulysses), for instance, is nearly as large and is arguably more spectacular in flight since the intense electric blue of the wings flickers like lightning.

They are a real challenge to the photographer since their flight is very fast and erratic and when they do settle, which happens rarely, they fold their wings and we see only the brown undersides.  (Any photo of a Ulysses resting with wings outspread has been staged to some extent – they don’t normally do it in real life for the very good reason that they would be fatally obvious to predators.)

Both of these photos, which show two different individuals visiting my garden yesterday morning, were taken while the butterflies hovered to feed from Pentas flowers; a fast shutter speed eliminates most of the blur, and taking lots of photos means that one or two will show the wings reasonably well.

Pentas (Pentas lanceolata), by the way, are our best year-round butterfly feeding plant, since they flower constantly and all species seem to appreciate the nectar. Oddly, the leaves are loved to death by the Hawk-moth caterpillars but not favoured by any of the butterfly caterpillars.

Ulysses Swallowtail feeding on Pentas
Ulysses Swallowtail

Hawk moths

Convolvulus hawkmoth, Agrius convolvuli
Convolvulus hawkmoth, Agrius convolvuli

Like the Rhinoceros beetle (previous post), hawk moths are wet-season visitors, with occasional strays turning up as late as the end of May and as early as the end of October. We get several species – Hypotion rosetta and some adults I haven’t identified such as this camouflaged brown one. They generally feed on the wing, like this one.

They often fly in around dusk so we don’t see them as often as we see their caterpillars, which spend all day eating their way through our Pentas plants and will do the same to Madonna lilies if given the chance. (We might like them a bit more if they liked the weeds, actually.) The caterpillars are large – here is one on my hand to give you an idea – and come in green, brown or black, often with eye-spots and usually with a horn on the tail end.

What’s around in mid June

I will try to make this a monthly update, as much for my own interest as for anyone else’s, although this time there is actually not much change from mid-May in either the weather or activity on the garden.

Our weather has mostly been settled in its standard, gorgeous, cool dry-season pattern – 10C overnight dawning to blue skies and a top of 24 (each temperature only varying by 2C either way) with low humidity. That pattern has been interrupted occasionally by a few days of cloud and a little rain but we have been watering the garden quite regularly.

As for the wildlife, it’s easier to say what’s different from last month than to list it all again. Of the butterflies, the Eurema, Hesperidae and Orchard Swallowtail have gone but all the others are still here and we now have quite a lot of the Dingy Bush Browns, Mycalesis perseus, and a few resident Melanitis leda. Of the moths, we now have few or no Hawk Moths but that’s the only difference. Everything else is much the same; there’s no reason why not, really, since the weather is much the same.

Days are a little cooler and shorter (and I do mean a little: the shortest day of the year is next week but we will still get 11 hours between sunrise and sunset). That does make the butterflies sleepy earlier in the afternoon; I caught these two Chocolate Soldiers bedded down for the night in a tangle of Pentas at about 3.30 this afternoon.

Two butterflies on Pentas flowers
Chocolate Soldiers (Junonia hedonia)